With debt payments needing to regularly roll over, if Congress doesn't pass a bill slashing appropriations to meet revenue minus interest, and if they also don't approve a debt ceiling increase, then it is about paying it back. They are typically debating just the ceiling half, which means if they dont pass it we default on the debts we owe.

I think that is the point of the Grandstanding by the conservatives last time. When all we have to do is borrow and borrow and borrow no one pays attention to the bills racking up but, if something had to get cut to pay for the other expenses, people might actually notice. Obviously we need to pay our bills but at some point we are going to have to have some correlation between revenue and expenditures.